Among the Imposters (Shadow Children #2)

Luke Garner is terrified. Out of hiding for the first time, he knows that any minute one of his new classmates could discover his secret: that he's a third child passing as the recently deceased Lee Grant. And in a society where it's illegal for families to have more than two children, being a third child means certain death at the hands of the dreaded Population Police.

His first experience outside the safety of his home is bewildering. There's not a single window anywhere in the school; Luke can't tell his classmates apart (even as they subject him to brutal hazing); and the teachers seem oblivious to it all. Desperate to fit in, Luke endures the confusion and teasing until he discovers an unlocked door to the outside, and a chance to understand what is really going on. But to take this chance -- to find out the secrets of Hendricks -- Luke will need to put aside his fears and discover a courage that a lifetime in hiding couldn't thwart.